Circuit controlling means



Jan. 26, 1937. w. H. FRANK ET AL CIRCUIT CONTROLLING MEANS Original Filed Nov. 13, 1933 INVENTORS fiwbww w. ZMA/ ATTORNEY.

Patented Jan. 26, 1937 PATENT OFFICE cmcurr CONTROLLING MEANS William H. Frank and Joseph Messing, Detroit, Mich, assignors to Bulldog Electric Products Company, Detroit, Mich., a corporation of West Virginia Original application November 13, 1933, Serial No. 697,859. Divided and this application December 22, 1934, Serial No. 759,452

5 Claims. (Cl. 200- 116) This application relates to circuit controlling means or circuit breakers and particularly to details of construction thereof, and is a division of our application Serial No. 697,859, filed November 13, 1933.

This application discloses in the annexed drawing novel combined overload and no-voltage release means for a circuit breaker. In this 'drawing,

Figs. 14 show in elevation and Fig. 5 shows in plan, circuit breaker parts and a combined overload and no-voltage release means for the same.

More specifically, I

Fig. 1 shows the parts in normal load and normal voltage condition;

Fig. 2 shows the parts when the breaker has been released by a voltage failure;

Fig. 3 shows the parts when released by an overload;

Fig. 4 shows the parts in the reset condition just prior to the re-establishment of normal volt-, age (full lines) and (in dotted lines) just after the re-establishment of normal voltage..

It will be understood at the outset that the circuit breaker is not here shown but is intended to be of the type that includes trip lever 90 which, when the breaker is closed, is down, and which, when the breaker is open, is up. The control arrangement of this application is designed to hold the trip lever 90 down, or to release it and permit the trip lever 90 to be moved up by a breaker spring not shown here.

The trip lever 90 is normally held down by the cross bar 9| which at one end is operatively connected to the overload holding means in the form of a tip 92 on the upper part of a conventional U- shaped bimetallic overload holding element 93.,

The other end of the cross bar 9| is provided with a latch 94 pivotally connected thereto and carried .thereby by a pivot pin 94a. and adapted. to be held by the tip 95 of a bimetallic thermally influenced current responsive element 96. I

It is understood that both of the thermal elements 93 and 96 are so connected and arranged with respect to the circuit to be controlled that element 93 occupies its position of Fig. 1 on normal load and warps due to the rise in temperature on overload, whereas element 96 occupies its position of Fig. 1 when its temperature is high due to the presence of a normal voltage on the controlled circuit and cools and warps back to the position of Fig. 2 when its temperature is reduced due to the absence of normal voltage from the controlled circuit.

In addition to the foregoing parts, the under voltage control means includes a spring 98 carried by the cross bar 9| and having a hill 98a, stops 99 carried by the cross bar 9| for determining the extremes of movement of the pivot latch 94, and a fixed pin I00 mounted on the circuit breaker base in a manner not shown, and useful under certain circumstances when resetting following releaseof the parts takes place.

The operation of the control means will now be described.

Normal load, normal voltage, Figure 1 Under such circumstances the parts are in the position of Fig. 1, and cross bar9| is held down,

7 to hold trip lever 90 down, at the left end by the tip 92 of the overload element 93 and at the right end by the engagement of latch 94 with the. tip 95 of the heated warping element 96.

Failure of voltage, Figure 2 In the eventvoltage on thecontrol line fails, there will becreated an absence of heating current for the warping element 96 and the latter will then cool, with a time delay action, and warp to the right. The initial movement of element 96 to the right will release latch 94 and the breaker spring will thereupon pull trip lever 90 and with it the right end of the cross bar 9| upwardly to the position of Fig. 2, the left end of the cross bar remaining fixed due to its being held by the tip 92 of the warping element 93 which is in its normal condition, and the circuit breaker will be open.

It is observed that latch 94 will not move clockwise when element 96 cools and warps to the right on an under voltage, in a manner to cause cross bar 9| still to be held by the tip 95 of element 96, because latch 94 is prevented from following element 96 by the engagement of the l wer end of latch 94 with the east side of hill 98a of the leaf spring 99.

Overload, Figure 3 To reset the breaker, trip lever 99 and cross bar 9| are moved down against the influence of the breaker spring in a conventional manner.

The left end of cross bar 9| will be held by the tip 92 of the overload element 93 which just prior to reset is necessarily in its holding position. The right end of cross bar 9| will be held by the tip 96 of the element 96 which during reset is necessarily in its cooled position shown in full lines, Fig. 4. To establish the connection between the cross bar 9| and the tip 96 the piv oted latch 94 must be utilized. If during reset the pivotal latch is tilted to lie from N. W. to S. E., the lower end of the latch 94 on reset movement will be engaged by fixed stop I06 and will be moved to the left over the hill 98a of spring 98 so that it will tilt to lie toward N. E. to S. W., whereupon its upper end can be disposed under the tip 96 of element 96; if latch 94 previous to reset had happened to be tilted to lie from N. E. to S. W:, stop I00 would not have to be relied upon.

When both ends of cross bar 9| are held, the parts are reset and the breaker remains closed. After it has been closed for an instant and normal voltage re-established, element 96 will heat up and warp to the left to the position of Fig. l, and in such movement latch 94 will move to lie from N. W. to S. E.

' During such movement of element 96 and latch 94 following the re-establishment of normal voltage, element 96 will not release its hold on cross bar 9| but will merely take up the lost motion connection provided by the pivoted latch 94.

Features An important feature or the construction herein disclosed-is the construction of the no-voltage holding and release means. The no-voltage means of the construction here disclosed includes as its principal element a bimetallic thermally influenced circuit current responsive warping element 96 simple in construction and eflicient of operation and connected to the breaker part 90 to be held by a lost motion connection of such a character as to permit reset without interfering with the trip free characteristics desired in breaker control.

Another simple feature is the characteristic that the element 96, as contradistinguished from the element 93, is in its warped condition under normal circumstances and cools to return to its normal condition under abnormal circumstances.

Another feature is the characteristic that the element 96 provides a time-delay release so that momentary under voltages will not cause the release of the breaker. Before an under voltage can cause breaker release, it must be of sufficient duration to deprive the element 96 of the heating current that maintains it warped for a sufliciently long time to permit the element 96 to cool and warp back to its normal position.

Another feature is the simplicity of the construction, obtained by using a single cross bar 9| as the holding element, and disposing an overload control at one end and an undervoltage control at the other.

What we claim is:

1. Circuit breaker holding and release means for a breaker part which when held maintains the breaker closed and which when released permits the breaker to open including a bimetallic, thermally influenced, circuit current responsive holding element so arranged with respect to the circuit to be controlled as to warp, on normal voltage, into holding p sition and to warp back, on failure of voltage, into release position.

2. Circuit breaker holding and release means for a breaker part which when held maintains the breaker closed and which when released permits the breaker to open including a bimetallic, thermally influenced, circuit current responsive holding element so arranged with respect to the circuit to be controlled as to warp, due to the heat created therein by the passage of circuit current on normal voltage, into holding position and to warp back, due to the cooling thereof by the absence of sumcient heating current on failure of voltage, into release position.

3. In a circuit breaker, a holding and release bar, normal load holding and overload released means at one end of said bar and in operative connection with said bar at such end, normal voltage holding and under voltage release means at the other end of said bar and in operative connection with said bar at such other end, and a circuit breaker part operatively connected to said bar to be held or released thereby.

4. Circuit breaker holding and release means for a breaker part whic when held maintains the breaker closed and which when released permits the breaker to open comprising a control part which is arranged to move in one direction on the establishing of normal voltage and to move in the opposite direction on the failure of normal voltage, and a lost motion connection between the breaker part and the control part so arranged that the breaker part may be moved into reset position and be held there automatically by the control part, even though the latter is in under voltage position, to hold the breaker closed even when the control part is in its under voltage position, the latter being arranged to automatically move itself, after the breaker is closed by reset movement of the breaker part to establish normal voltage, to take up such lost motion, without relinquishing its hold on the breaker part during its movement from under voltage position to normal voltage position.

5. Circuit breaker holding and release means for a breaker part which when held maintains the breaker closed and which when released permits the breaker to open comprising a control part which is arranged to move in one direction on the establishing of normal voltage and to move in the opposite direction on the failure oi. normal voltage, and a lost motion connection between the breaker part and the control part so arranged that the breaker part may be moved into reset position and be held there automatically by the control part, even though the latter is in under voltage position, to hold the breaker closed even when the control part is in its under voltage position, the latter being arranged to automatically move itself, after the breaker is closed by reset movement of the breaker part to establish normal voltage, to take up such lost motion, without relinquishing its hold on the breaker part during its movement from under voltage position to normal voltage position,'the lost motion connection being such that initial movement of the control part out of its normal voltage position and towards its under voltage position releases the breaker part, the lost motion connection being inoperative to cause the breaker part to be held by the control part during any part of such movement of the control WILLIAM H. FRANK. JOSEPH LEESSING.

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